Synthetic resin and method of preparing the same



Patented Dec. 24, 1935 SYNTHETIC RESIN AND METHOD OF PREPARING THE SAME Roy H. Kienle, Schenectady, N. "1., assignor to General Electric Company, a corporation or New York No Drawing.

Application August 25, 1933, Serial No. 686,780

6 Claims. (01. 100-22) The present invention relates to synthetic resins and methods of preparing the same. More specifically it is concerned with alkyd type resins which may be prepared in various degrees of flexability, which are relatively quick curing, oilcured flexible alkyd resins.

resistant and stable in character.

In a copending application 01' Saflord, Serial No. 613,563 filed May 25, 1932, and assigned to the assignee of the present invention there are disclosed andclaimed resinous compositions which are prepared by compounding in correct proportions semi-cured (or partially cured) and totally Such resinous compositions are capable of being extruded through shaped dies and worked on rubber compounding rolls like rubber. In fact, the compositions are rubber-like in character, their flexibility, resiliency and plasticity depending on the nature and amount of ingredients used intheir preparation.

I have been able to materially improve the cure time, water resistance and general stability of this type of resinous composition by using instead of the semi-cured flexible alkyd resin portion a semi-cured resin prepared by reacting a phenol and an aldehyde in the presence of an alkyd resin catalyst in accordance with the disclosure in the copending application of Kienle and Schlingman, Serial No. 653,673, filed January 26,

1933, which application is also assigned to the asslgnee of the present invention. Moreover, I have been able to efiect such results without any corresponding loss in such properties as flenbility and oil resistance of the products which is rather surprising since the addition of resins of the phenolic type would not be expected to yield such results normally.

In order that my invention may be more fully understood and practiced by those skilled in the art to which it pertains the following examples thereof are given it being understood that they are merely illustrative in nature. 1

Example 1 by weight 01' this resin were dissolved in 37.4 parts by weight of phenol. 17.2 parts by weight of paraformaldehyde were then added and the ingredients cooked under reflux for about 3 hours. The temperature was allowed to rise slowly to I 115 0., then to drop to about 105 C. At this point 13.3 parts by weight of dibutyl phthalate and 30 parts by weight of phthalic anhydride were added and the heating continued at to C.

in the open until a cure of 25 seconds on aa G. 10 hot plate was reached. Upon pouring into a suitable container and cooling, the resin was ready for use. I

In the above example the ratio of alkyd resin to phenolic resin was 35 to 65, that is the resinous" composition contained 35% flexible alkyd resin. This ratio can vary from 20% to 80% and thus the flexibility of the resinous composition can be varied.

The resinous composition above prepared was" in the semi-cured state. It was used in conjunction with a fully cured alkyd resin to prepare the flnal product. Using this semi-cured resin a product was prepared by milling together on heated rubber compounding rolls: 25

Parts by weight Semi-cured resin as above prepared (binder resin) Granulated fully cured flexible alkyd resin prepared by reacting glycerol, phthalic anhydride, glycol and adipic acid (ratio 3.5 to 1 glycol adipate to glycerol phthalate)- 73 Zinc stearaf 2 After sheeting, a tan, homogeneous plastic 35 mass resulted which could be calendered, extruded or molded. When molded into sheets approximately thick, a satisfactory cure was obtained using a temperature of 150 C. for onehalf hour. A tough, flexible sheet resulted which was suitable for cutting oil-proof gaskets, washers, etc.

To illustrate the improvement obtained when a semi-cured resin oi. the type I employ herein 5 as the binder resin is used instead of the ordinary semi-cured flexible alkyd resin, 9. comparison is made in the table below of some of the properties exhibited by a compound made in accordance with Example 1 and a similar com- 5 pound made with semi-cured flexible alkyd resin.

Same mix with B- sta e flexible alkyd res n binder 82'! M 202 21-28 hours at 150 0.

Compound of Example 1 when: cold water ML--.

The above table clearly shows how the curing time and water resistance are improved without adversely affecting other properties.

Example 2 An A-stage flexible alkyd resin was'prepared in the usual manner using a ratio of 10 mols glycol adipate to 1 mol glycerol phthalate. The resin was cured at 180-200 C. to C-stage in a heated dough mixer, 10% lead oxide being added just at gelation.

Using the binder resin (semi-cured resin) prepared in Example 1 a. plastic compound was mixed on heated rubber rolls using the following ingredients: Y Parts by weight Cured C-stage flexible alkyd resin 78 Binder resin 20 Zinc stearai 2 A dark tan compound resulted. When pressed between platens at 150 C. for one-half hour this compound cured to a rubbery, flexible, tough sheet, resistant to oil, water and other similar agencies.

Example 3 A flexible alkyd resin was prepared as above using a ratio of 15 mols glycol adipate to 1 mol glycerol phthalate. It was cast into sheets, cured to C-stage and ground to a meal on rubber compounding mils.

A plastic compound was made up using the following formula:

Parts by weight C-stage flexible alkyd resin "l8 Binder resin of Example 1 20 Iron oxide 2 A binder resin was prepared by dissolving in 8.25 parts by weight of phenol at about C., 3.5 parts by weight of an A-stage flexible resin (prepared by using a mol ratio of 3.5 to 1 glycol adipate to glycerol phthalate), acid number about 200. When the resin was dissolved 4.25 parts by weight of paraform were added and the whole mass heated under reflux at a temperature between to C. After four hours of refluxing. 2.5 parts by weight of dibutyl phthalate and 0.65 parts by weight of phthalic anhydride were added and the resin further cooked down under reduced pressure at a temperature of 90 to 100' C. to a thick syrup having a 20 second cure on a C. hot plate. A compound was prepared from:

Parts by weight 15:1 C-stage flexible alkyd resin as Binder resin (as above prepared) 10 Iron oxide 2 After mixing, sheeting and curing for 1% hours at 150 C., a flexible, tough, leathery sheet 10 with high tensile strength was obtained. The cured sheet had a hardness of 30 (Shore hardness) Example 5 I A flexible binder resin was prepared by reacting in the manner outlined in Example 4:

. Parts by weight Phenol 10.1 Paraformaldehyde 5.6 20

3.1 flexible alkyd resin (acid No. -210) 7.0

After boiling down under vacuum, a thick semiliquid resin resulted. This resin was used with B and C-stage granulated 3%:1 flexible alkyd A gray flexible sheet resulted which could be calendered, molded and extruded. After calendering into a thin sheet 10-20 mils thick, wrapping several layers onto a mandrel to A to Y4 35 inch thickness, tightly binding with cotton sacriflce tape and curing 1 to 4 hours at 200 (3., a homogeneous, flexible, oil-proof sleeving resulted.

Example 6 40 Using the same flexible binder resin described in Example 5, a compound was made from the.

following:

Parts by weight 15:1 C-stage adipic type flexible alkyd resin "1'7 45 Binder resin 20 Litharge 2 Zinc stearate 1 An easily workable, flexible sheet resulted which could be sheeted, calendered, pressed, and mold- 5 ed. After curing for 1% hours at 150 C. the prodnot was a tan, leathery homogeneous compound.

It is apparent that the examples given above are merely illustrative as to proportions, ingredients, etc. to be used. For example, aqueous 5 formaldehyde may be used in place of para-formaldehyde. Cresols, xylenols, hydroxydiphenyl, etc. can be used in place of phenol. Any of theknown alkyd resins, for example, the fatty acid and oilmodifled types, can be substituted for the alhd resins used in the preparation of the compounds illustrated above.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The process which comprises compounding 55 a totally cured resin formed from a mixture comprising a polyhydric alcohol having three or more hydroxyl groups in the molecule, a polybasic organic aromatic acid, a dihydric alcohol and .a dibasic aliphatic acid; with a partially cured resin 70 which has a cure point of 20-25 seconds at 150 C. and which is formed by reacting a phenol and an excess of aldehyde in the presence of a fusible, soluble acidic alkyd resin of acid number about 200; and curing the compounded mass at 75 a temperature of ISM-200 C. to a homogeneous, flexible product.

2. The process which comprises compounding under heat and pressure totally cured resin i'ormed by reacting a polyhydric alcohol having three or more hydroxyl groups in the molecule. a polybasic organic aromatic acid, a dihydric alcohol, and a dibasic aliphatic acid; with a partially cured resin which has a cure point of 20-25 seccnds at 150 C. and which is formed by reacting a phenol and an excess of paraiormaldehyde in the presence of a fusible, soluble acidic alkyd resin of acid number about 200 in proportions such that the compounded mass is quick curing to a flexible, water-resistant and oil-resistant product.

3. A flexible, plastic moldable composition comprising a totally cured resin formed from a mixture comprising a polyhydric alcohol having three or more hydroxyl groups in the molecule, a polybasic organic aromatic acid, a dihydric alcohol and a dibasic aliphatic acid; said totally cured resin being mixed with a relatively small proportion of binder comprising a partially cured resin which has a cure'point of 20-25 seconds at 150' C. and which is formed by reacting a phenol and an excess of aldehyde in the presence oi a fusible, soluble acidic alkyd resin oi. acid number about 200. 5

4. A flexible, oil-resistant and water-resistant composition comprising the product of cure under heat of the composition oi claim 3.

5. A quick curing moldable composition comprising a mixture of fully cured flexible alkyd 10 resin formed by reacting under heat glycerine, phthalic anhydride, glycol and adipic acid; and a relatively small proportion of binder comprising a partially cured resin which has a.cure point. 16 of 20-25 seconds at 150 C. and which is formed by reacting a phenol and an excess of paratormaldehyde in the presence of a fusible, soluble acidic alkyd resin 01' acid number about 200.

6. The flexible, oil-resistant and water-resis ant product of cure under heat of the composi- I tion oi claim 5.

ROY H. KIENLE. 

